"I'm trying to get to a point to come back to be able to step on the football field again in whatever capacity that is," Manziel said. "I am watching all the other guys doing what I want to be doing, and I am sitting on a couch being a loser."

A former Heisman trophy winner and first-round draft pick, Manziel's two seasons in the NFL were overshadowed by off-field controversies surrounding Manziel's antics and drinking.

Now, however, Manziel says that he has quit drinking after being diagnosed with depression and bipolar disorder.

"For a while I got so ingrained, caring only about what Johnny wanted, only caring what mattered to me, what made me happy. When I look back at it now, even when I thought I was doing what I wanted, I was miserable," he said.

Manziel admits that for years, "I was self-medicating with alcohol. That’s what I thought would make me happy and get out of that depression."

Now, however, Manziel says that he is making his mental health "a priority" in his life. He has stopped drinking, and was diagnosed with bipolar disorder around a year ago.

"I am taking medication for bipolar, and I am working to try to make sure I don’t fall back into any type of depression, because I know where that leads me and I know how slippery a slope that is for me," Manziel said.

As far as his comeback goes, Manziel "100%" hopes to get back to the NFL, but he admits, "I am coming back from a huge downfall. I don’t know what kind of comeback it will be, but I know I want to get back on a football field, to what brought me so much joy in my life."